Rising global temperatures are expected to significantly increase the incidence of dengue fever, a mosquito-borne disease. A recent study led by Marissa Childs at the University of Washington predicts that cases could surge by as much as 76% by 2050. This alarming forecast highlights the impact of climate change on public health across large areas of Asia and the Americas.
Dengue fever, which typically presents with flu-like symptoms, can escalate to severe illness without proper medical care. The disease has previously been confined mostly to tropical regions, but recent trends indicate a broader geographical reach due to warming climates. The research, published on September 9 in the journal PNAS, is regarded as the most comprehensive analysis of how temperature changes influence the spread of dengue.
Childs, who conducted much of this research during her doctoral studies at Stanford University, noted, “The effects of temperature were much larger than I expected. Even small shifts in temperature can have a big impact for dengue transmission, and we’re already seeing the fingerprint of climate warming.”
The study evaluated over 1.4 million observations of dengue incidence across 21 countries in Central and South America and Southeast and South Asia. Researchers found that dengue thrives at an optimal temperature of approximately 27.8 degrees Celsius (or 82 degrees Fahrenheit). While regions that are currently cooler are expected to see significant increases in cases, areas that already experience high temperatures may experience slight declines.
The findings indicate that climate change has contributed to an average 18% increase in dengue incidence across the studied regions from 1995 to 2014. This translates to more than 4.6 million additional infections annually based on current incidence estimates. Projections suggest that if greenhouse gas emissions remain unchecked, dengue cases could increase by another 49% to 76% by 2050, particularly impacting areas with high population densities in countries like Mexico, Peru, and Brazil.
Senior author Erin Mordecai, a professor of biology at Stanford University, emphasized the uniqueness of this study. “Many studies have linked temperature and dengue transmission,” she explained. “What’s unique about this work is that we are able to separate warming from all the other factors that influence dengue—mobility, land use change, population dynamics—to estimate its effect on the real-world dengue burden.”
The researchers cautioned that their estimates might be conservative. They do not consider regions where dengue transmission is sporadic or poorly documented, nor do they include large endemic areas like India and Africa, where data is often lacking. Recent locally acquired cases in areas such as California, Texas, Hawaii, and parts of Europe highlight an expanding range for dengue.
Urbanization, human migration, and the evolution of the virus could amplify the risks associated with dengue transmission. At the same time, medical advances may mitigate some of these threats, creating uncertainty in future projections. The study suggests that aggressive climate change mitigation efforts could significantly reduce the burden of dengue disease.
Adaptation strategies will also be critical. These include enhanced mosquito control measures, strengthening health systems, and potentially widespread use of new dengue vaccines. The findings serve as a critical tool for public health planning and emphasize the need for accountability from governments and fossil fuel companies regarding climate change damages.
“Climate change is not just affecting the weather—it has cascading consequences for human health, including fueling disease transmission by mosquitoes,” Mordecai stated. “Even as the U.S. federal government moves away from investing in climate mitigation and climate and health research, this work is more crucial than ever for anticipating and mitigating the human suffering caused by fossil fuel emissions.”
Co-authors of the study include Kelsey Lyberger of Arizona State University, Mallory Harris of the University of Maryland, and Marshall Burke of Stanford University. Their research received funding from various sources, including the Illich-Sadowsky Fellowship at Stanford University, the National Institutes of Health, and the National Science Foundation, among others.
